I love this answer. I’m inclined to think that our anonymous interlocutor is revealing a key truth about how the other half (closer to one percent, probably) lives in San Francisco. I’ve never had money enough to live high on a hill in the city, and hadn’t heard of this vexing problem. A quick search turns up one brief about the difficulties of life on the less posh, but still very desirable, Potrero Hill, as noted by the Potrero View in 2010:

Plumbing
For years Potrero Hill residents have complained about low water pressure; apparently they have reason to do so. According to Thomas Friel, who offers plumbing service from his Connecticut Street office, it takes one pound of pressure to raise water two feet uphill, and pressure gets used up as water is pumped higher. Friel said low water pressure is common on the top of the hill, and offered some solutions, including removing devices that restrict water flow, and conserve water, from faucets and shower heads. “You’re not wasting water by removing it,” said Friel, “you actually need more water flow [in] your shower head and faucets to enjoy the same amount of water that your neighbors in the high pressure areas enjoy.” If that doesn’t work, another option is to install a booster pump and pressure tank in the cold water supply to provide extra pressure. Though a more expensive fix, “that will give you a lot better shower,” said Friel.